Border less window mode

Disable ugly grey windows borders. Especially beautiful for the Quake mode.

Now for the development branch. Copy of the https://github.com/bliker/cmder/pull/320

And with screenshot of the borderless cmder when quake mode is enabled.
![borderless_cmder](https://cloud.githubusercontent.com/assets/5702278/5112881/ff8bfad0-6fdf-11e4-911a-5380a97f48cb.png)